Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already mark the tool as read-only and idempotent. The description adds meaningful behavior beyond that: current-week defaults, timezone-dependent week boundaries, days_left calculation, and UTC fallback behavior. This is exactly the kind of extra context agents need.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with a clear purpose and use case, followed by useful timezone context. The 'Args' block at the end is slightly redundant with the input schema, but the overall structure is organized and free of fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the output schema, read-only annotations, and thorough description covering default behavior, timezone edge cases, and parameter usage, nothing critical is missing for an agent to select and invoke this tool correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already fully documents week_start and timezone. The description mostly paraphrases the schema, adding only modest nuance about timezone affecting week selection and days_left. This is marginal value beyond structured input definitions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Get a coaching summary for one Monday-Sunday training week.' It then enumerates the exact content areas returned, making it easy to distinguish from siblings like get_schedule or get_workout_detail.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It explicitly says 'Use it when planning a workout' and explains when to pass timezone vs when UTC will be used. It does not name alternative sibling tools or state when not to use this tool, but the contextual guidance is clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.